Conventional medical imaging systems, such as imaging catheters and the like, are capable of imaging the interior of an internal body lumen, such as a blood vessel, in a two dimensional (2D) manner. In 2D imaging, variations in the cross section and width of the body lumen are visible. However, in a three-dimensional (3D) reconstruction, such as reconstructed 3D image 20 of blood vessel 10 depicted in FIG. 1, the lumen itself will appear as being straight or uni-directional, i.e., any curves or bends in the lumen along the length of the lumen are not visible. This is because the lumen is imaged by sliding the imaging device along the length of the lumen while at the same time imaging multiple consecutive cross sections of the lumen. The 3D reconstruction of the lumen is created by merging these multiple cross sections together. However, because the imaging devices are incapable of providing information on the lateral spatial relationship between cross-sections, i.e., whether the position of these cross sections change relative to each other, the 3D reconstruction of the lumen must therefore assume that the lumen is straight and merges the cross sections together accordingly.
Because the presence of bends and curves in the lumen can impact many medical procedures, this limitation significantly reduces the number of diagnostic and therapeutic applications in which 2D imaging systems can be used. For instance, curves, twists and other variations in the 3D structure of a lumen can effect distance and area measurements taken along the lumen. Also, as another example, the degree of success in stent deployment procedures, such as whether the stent was properly deployed along a straight segment of a blood vessel, cannot be readily or efficiently determined.
Accordingly, improved 3D imaging systems are needed that can display the full 3D structure of internal body lumens.